His first big test

Gordon Brown's friends compare him to a grand master - a strategist, always thinking several moves ahead. That approach served him well at the Treasury, where the regular cycle of budgets and spending rounds lent itself to meticulous advanced planning. But now he is prime minister and much of his work will involve reacting - because stuff happens and, when it does, it now falls to him to give a lead. That reality was underlined yesterday when, in the midst of a transition that had so far proved more stable and orderly than Labour had dared to hope, the police looked inside a Mercedes parked in the heart of London and discovered a large bomb. Before long there were reports of further alerts, in other parts of the city. It seemed possible, at least, that terrorists were showing the same cynical alertness to the political calendar displayed in 2004, when nearly 200 people were murdered on Madrid's commuter trains on the eve of a Spanish general election.

Suddenly, the ingenious emerging architecture of the new government's middle-tier seemed less exciting. The question that seemed to matter was how Mr Brown would respond to the terrorist threat. He had to show he could act without surrendering his famed strategic sense. The big risk was that he would succumb to the temptation to win spurs as a warrior against terrorism by overreacting. That is what Tony Blair did soon after the 2005 London bombings, when - without having properly squared colleagues or attempting a to build a consensus with opposition parties - he stood up and announced that "the rules of the game have changed" and committed himself to eye-catching, draconian measures. That approach did not make Britain a more secure country; instead it ended up with the government defeated in the House of Commons on the question of whether terror suspects could be detained for 90 days without trial or charge.

It is far too soon to say whether Mr Brown will do better, although the signs yesterday were encouraging. Properly, he called for vigilance in the face of a "serious and continuous" threat. But he did not seek to play up the danger, or to capitalise on it. The new home secretary, Jacqui Smith, was allowed to take much of the limelight, and her remarks displayed a refreshing realism by acknowledging the impossibility of entirely eliminating security risks. And far from using the incident as a chance to set himself up in populist opposition to libertarian concerns, Mr Brown pressed ahead with announcing that the Liberal Democrat lawyer Anthony Lester, a dogged defender of civil rights, will be appointed as a ministerial adviser.

That appointment was one of several designed to show that Mr Brown can transcend the tribalism of which he has often been accused. Even more striking was the appointment of professional experts as ministers in their own right: the former admiral and intelligence chief Sir Alan West was installed at the Home Office, and the medical professor Sir Ara Darzi at health. Not all of yesterday's appointments, however, will be without controversy. Campaigners against forcing liberalisation on developing countries might be surprised to see that the trade portfolio has been handed to Sir Digby Jones, who previously led the CBI, which has called for countries such as Brazil and India to open their markets. And the ministerial arrival of his former aide Shriti Vadera, who does not enjoy a reputation as one of the easiest of people to work with, reveals that Mr Brown has not totally dispensed with his past exclusivity.

This morning's Guardian/ICM poll, with a four-point lead for Labour - earned at the expense of the Liberal Democrats, not the Conservatives - confirms that the transition has been going well for the new prime minister. By refusing to resort to the politics of fear at the first hint of the terror threat, Mr Brown yesterday gave reason to hope that his administration might feel refreshing for some time to come.